One-piece shaft construction and a method of construction using bladder molding

ABSTRACT

The present invention discloses a method of fabricating a composite material hockey stick shaft using internal bladder pressure molding technology. The bladder is inserted over a mandrel and composite materials are disposed on the bladder forming a soft, uncured piece. The mandrel is removed and the piece is disposed in a mold following which air pressure is applied to the bladder which deforms the piece to conform to the shape of the cavity. The addition of pressure and heat cures the composite materials and produces a finished hockey stick shaft.

BACKGROUND OF THE INVENTION

[0001] The present invention relates to sporting equipment shafts and inparticular to shafts suitable for use in high-impact, high-velocity, andhigh wear and tear sports such as ice hockey, street hockey, in-lineskate hockey, ringuette, field hockey, lacrosse and other such sports.The present invention, by way of example only, will be describedhereinafter in relation to ice hockey sticks, but it is understood thatthe invention herein described and claimed may be suitably adapted toother shaft applications and in particular to other sports.

[0002] At present, hockey sticks may be generally broken down into twobroad categories, namely wooden hockey sticks, which shafts aregenerally made of wood such as any suitable hardwood, for examplehickory, maple, etc., and composite sticks, which shafts are made ofcomposite materials, such as carbon fibre, Kevlar™, fibreglass, andother such materials or combination of materials. The present inventionrelates to composite hockey sticks.

[0003] Composite hockey sticks generally consist of two basiccomponents, namely an elongated, narrow shaft and a blade secured to thelower end of the shaft. Composite hockey sticks may be generallyconstructed by gluing, assembling or otherwise bonding together the twoseparately fabricated components, namely the shaft and the blade. Inparticular, in accordance with known methods of construction ofcomposite hockey sticks, a tenon may protrude from the blade component,which tenon may be inserted into and secured to a hollow end of theshaft. Thus, after the shaft component is constructed, and after theblade component is constructed, the two components are mated byintroducing the tenon into a hollow portion at one end of the shaft,which hollow portion is sized and configured to receive the tenontherein. Presently, adhesives, glues and other bonding agents are usedto securely fasten the two components together so as to form a compositehockey stick. Thus, composite hockey sticks presently on the market maycomprise a shaft and a blade which are independently fabricated, andwhich are then subsequently bonded together in a secondary operation.The bonded assembly, and in particular the joint, may then becamouflaged under layers of paint, fillers or other materials, in orderthat the consumer views the composite hockey stick as being continuous,i.e. made of one piece.

[0004] The independent fabrication of a composite shaft and blade, andtheir subsequent secondary bonding through the use of adhesives or otherbonding agents, causes a structural stress riser or weak spot at, or inthe vicinity of, the bonded joint. This stress riser may cause the shaftto become weak at or near the joint, and may often cause prematurefailure in the shaft when the composite hockey stick is in use. Inparticular, slapshots, wrist shots and other hard shots which transfertremendous forces and stresses onto the shaft of the hockey stick, mayoften result in a composite hockey stick breaking at or near the jointof traditional composite hockey sticks presently on the market. Thepresence of a weak point is understandably not desirable in a shaft usedfor high-impact, contact sports such as hockey, lacrosse, etc . . . Inaddition, a weak point may, in some circumstances, be dangerous to otherplayers on the ice, or to bystanders, and in any event is unacceptableto consumers who may view unfavourably expensive composite sticks whichbreak prematurely.

[0005] It is thus an object of the present invention to provide for acomposite hockey stick wherein the secondary, subsequent bondingoperation of the shaft to the blade is eliminated so as to provide aone-piece shaft construction.

[0006] It is a further objective of the present invention to reduce oreliminate the stress riser or weak spot which is normally found alongthe shaft at the position of the joint, so as to increase the longevity,strength and serviceability, of a composite hockey stick.

[0007] It is a further advantage of the present invention to provide fora composite hockey stick having increased strength and durability inparticular along the shaft thereof.

[0008] It is a further object of the present invention to provide animproved composite hockey stick, and an improved method of constructionof a composite hockey stick.

[0009] It is a further object of the present invention to provide amethod of construction for a composite hockey stick using bladdermolding technology.

SUMMARY OF THE INVENTION

[0010] The present invention generally provides for a composite hockeystick shaft wherein the bonded joint as known today in the prior art (ofthe shaft component with the tenon of the blade component) may beeliminated or substantially eliminated. In particular, known compositehockey stick shaft technology, which uses a method through which twopieces of composite sticks, namely the composite shaft and the compositetenon are subsequently bonded together in a secondary step through theuse of glue or another bonding agent may be eliminated.

[0011] It has been found that conventional composite hockey stickswherein the tenon is secondarily mated to the shaft, i.e. at the lowerend of the shaft, for example at 15 to 20 inches above the bottom of theblade, may have a structural riser or a weak spot at or near the bondedjoint. Since it is well known that a tremendous level of stress andforce is applied to the shaft of a stick during play, and in particular,during a slapshot, wrist shot or during checking, it is important toreduce or eliminate the presence of any weak point(s) on a shaft. Inparticular, the forces applied during play may be concentrated on thelower end of the shaft. Thus, eliminating or reducing a weak point inthe shaft, and in particular, on the lower end of the shaft, may be ofprimary importance for the longevity and for the serviceability(performance) of the stick, in particular for professional or highcaliber play. Thus, the elimination or reduction of this stress riserthrough a one-piece shaft may significantly improve the life and theperformance of a composite hockey stick.

[0012] The present invention is directed at providing a unitary, orone-piece composite hockey stick shaft, wherein the composite shaft andthe composite tenon may be mated, before the application of any orsubstantially any pressure to the shaft and to the tenon for curing ofthe composite materials. Thus, in accordance with the present invention,the curing of the shaft and of the tenon and the bonding of the shaftand of the tenon together may occur at the same time, once the tenon ismated to the shaft. In this manner, the resulting composite hockey stickmay be made as much as possible as a true, unitary or one pieces stick.

[0013] Conventional composite hockey sticks may be manufactured inseveral steps. In accordance with one embodiment, the present inventiondeparts from that approach in some ways, namely in that the curing, i.e.final curing, of the composite materials of the shaft and of the tenonis delayed, or at least partially delayed, until the previouslyconstructed tenon is mated to the previously constructed shaft. Thus,because an uncured, or partially uncured, composite tenon is introducedinto an uncured or partially uncured shaft (or vice versa), the curingof the shaft and tenon or the final curing or the completion of thecuring of one or both of the shaft or tenon occurs after the mating ofthe two. The resulting shaft/tenon combination may therefore result in asingle continuous piece wherein the curing, or the final curing of thematerial, will occur after mating. In this manner, the material of thetenon, and the material of the shaft may be bonded together and cured ina single step/operation occurring at the same time, which may result insaid materials being of a unified single bond.

[0014] Traditional composite hockey stick shaft construction may beaccomplished in a number of ways. Manufacturers may begin with what areknown as prepregs, i.e. composite materials which may be pre-impregnatedwith resins, such as epoxy resins or any other resins, compositematerials having any number of properties. Any number or combination ofcomposite materials may be used in the construction of composite shafts,such as carbon fibres, Kevlar™, fibreglass, viscoelastic film adhesives,and so on. In particular, fibres, such as carbon fibres, may be disposedso at to be unidirectional or may be woven in any number oforientations, for example, orientation of ±90 degrees to thelongitudinal axis of the shaft. The prepregs may also be braided, orincorporate therein any number of other materials or combination ofmaterials. The prepregs may be purchased frozen from a manufacturer, andkept in a freezer prior to their use (application), in order to reduceor retard the curing of the resin(s).

[0015] The fabrication of the shaft and of the tenon may occur in avariety of ways. A form, known as a mandrel, made of steel, aluminum orother material may be used around which the composite materials may bewrapped, woven or applied, or any combination thereof. The core may thenbe removed following the application of pressure. Some manufacturers mayuse a foam core which is left inside the finished, i.e. cured, shaft.The subject matter of the present invention may be used with compositeshafts and tenons which are constructed in any number of ways, using anynumber or combinations of materials, so long as they utilize the methodof mating the shaft and the tenon.

[0016] In addition, the present invention may eliminate or reduce theneed for body fillers, some known as Bondo™, to cover the manufacturingjoint of some composite hockey sticks presently sold on the market. Thisbody filler may often be used to mask the joint and to give theimpression that the shaft-tenon combination is a seamless one.Naturally, the use of additional material whose use is only cosmetic andtherefore not structural, adds only weight, without any resultingincrease in performance, such as strength or resilience. This results ina heavier stick without any compensating advantage and is therefore tobe avoided.

[0017] In accordance with a further particular aspect of the presentinvention, there is provided for a method of manufacture wherein bladderpressure technology is utilized to apply internal pressure to thecomposite materials which are used in the construction of a compositeshaft so as to cure the resins impregnating the composite materials.Further, the present invention provides for a hockey stick shaft whichis constructed using said method of manufacturing. In accordance withthis embodiment, the pressure which may often be applied to cure theresin soaking composite material may be accomplished through theapplication of internal pressure against a stationary outside objectwhich may resist the application of internal pressure.

[0018] In accordance with a particular aspect of the present invention,the method of construction of a composite hockey stick provides for theuse of a mandrel, i.e. a form, which have a generally round or circularconstant cross-section and which has an elongated length, namelyslightly longer (for example 5%, longer) than the finished shaft of thehockey stick to be assembled. The cross-sectional shape of the mandrelmay be other than circular, i.e. it may be oval or rectangular, and maynot be constant throughout the length of the mandrel, althoughdifficulties in applying, i.e. rolling the composite material theretomay have to be overcome. The mandrel may also combine several differentshapes and sizes. The mandrel may be sized so as to have substantiallythe same size (circumference) as the size, i.e. outside diameter of afinished hockey stick shaft. For example, the circular mandrel may havea circumference which is approximately 95% of the total outside lineardimension of the finished rectangular cross-sectioned hockey stickshaft. Alternatively, the mandrel circumference may be anywhere from 80%to 99% of the outside dimension of the finished shaft.

[0019] Prior to assembling the hockey stick shaft on the mandrel, themandrel is first fitted with a bladder thereon, which is inserted overone end and pulled over the mandrel to the other end thereof. Thebladder may be shaped like a sheath or sleeve and is closed off (or maybe closed of after insertion) at one end so as to be air (i.e.fluid)-tight. Generally, the bladder may be tight fitting on themandrel, although it is understood that it may be somewhat loose aboutthe mandrel so as to facilitate the subsequent removal of the mandrel.Although a variety of materials may be used as a bladder, such as nylon,rubber, silicon and latex, it is in any event preferred that the bladdermay be as thin as possible, yet strong enough to withstand the rigors ofinflation, as well as heat and pressure application which are to beapplied during the construction of the hockey stick shaft. In addition,the bladder may be of sturdy construction so that more than oneinflation and heat/pressure application may be applied to theconstruction of a shaft, and such that the bladder may be re-used in theconstruction of more shafts. In accordance with a particular embodiment,the thickness of the bladder may be {fraction (2/1000)} of an inchthick. In any event, the bladder must be suitable for its intendedpurposes, and in accordance with a particular application, be able towithstand pressure in the range of 0 to 200 pounds per square inch, andtemperatures of over 290° F.

[0020] The mandrel having been sheathed with a bladder, the prepregs aspreviously described are applied thereon in any variety or combinationof manners, using one or more combinations of several compositematerials. In accordance with one particular embodiment, the prepregsmay be rolled on the mandrel, either manually or mechanically. Duringthe application of the prepregs, a slight pressure may be appliedthereon, typically of the order of 10 to 20 pounds per square inch. Thispressure, known as ‘bulking pressure’, may be used to remove entrappedair which may be found in the prepregs, or between layers of prepregs,as a result of their application, as well as to consolidate the layersof composite materials together on the mandrel. Although a small amountof curing of the composite material may occur during the application ofbulking pressure, this may not the curing necessary to solidify thecomposite material to their final and desired form and strength. As maybe understood to one versed in the art, the prepregs may be applied inany manner or combination of manners, and for example, may be applied soas to be disposed at a particular angle or combination of angles inrelation to the longitudinal axis of the shaft. Further, the prepregsmay also be applied on the bladder in a pre-assembled manner.

[0021] Once the prepregs have been applied as desired or required, themandrel may be removed, leaving behind the bladder and the prepregswhich are disposed thereon. The mandrel may be removed through theapplication of manual or automated mechanical pressure, through, forexample, the use of a fixture affixed thereon, and/or through the use ofa twisting motion so as to disengage and pull out the mandrel. At thispoint, the prepregs may have the consistency of putty, or other soft,deformable materials, and may, for example, be (slightly) deformablethrough the application of gentle, manual pressure. As may beunderstood, once the mandrel is removed, there is left a hollow,cylinder-shaped, thin-walled combination of soft prepregs applied to theoutside of the bladder. The whole combination may then be ready forfurther processing.

[0022] Once the mandrel is removed, the prepreg-bladder combination,known as the piece, may be inserted inside a hollow mold or cavity,which may be known as a tool. The tool may be cut, made or constructedfrom a suitable material, such as steel, aluminum, brass or othermaterial and may, for example, be substantially elongated, and U-shapedin depth. The purpose of the mold may be to help impart the final shapeof the shaft to the piece, both longitudinally and cross-sectionally.Thus, in accordance with a particular embodiment, the tool may be madewith a computer numeric cutter (CNC) machine, which may make one or morecuts or incision into a die, which may be roughly the shape of afinished hockey stick shaft, i.e. it has substantially the length of ahockey stick shaft and (a portion of) its cross-sectional depth.

[0023] It is understood that the tool may need two or more components inorder to be able to function as a mold for imparting the final shape tothe shaft. For example, the tool may comprise a lower cavity and anupper cavity, each having substantially the same size, configuration andshape so as to simply be the mirror image of the other, i.e. inverted.In this embodiment, the depth (i.e. the depth of the hole) of each ofthe lower cavity and upper cavity may be substantially the same.Alternatively, the tool may have an upper and a lower cavity which arenot identical in size, one being deeper than the other. In a furtherembodiment, the tool may only have a lower cavity, into which the pieceis to be disposed, and an upper cavity which is only to act as a lidtherefor. In this manner, substantially all of the shape of the shaft isimparted by the cavity, with the lid acting to keep the piece in thetool. As may be understood, the tool may be configured and disposed in anumber of manners.

[0024] In any event, the cavity of the tool, namely the upper cavity andthe lower cavity may be configured and disposed so as to mirror theoutside shape, size and configuration of a finished hockey stick shaft.For example, the tool may be elongated (up to 60 or 70 inches long), andmay have two major surfaces which are spaced-apart by two minorsurfaces. In accordance with a further embodiment, the major surfacesmay be parallel to each other, and the minor surfaces may be parallel toeach other, the whole forming a regular parallelogram. In addition, themajor surfaces and the minor surfaces may each be planar. Further, thecorners where the major and minor surfaces meet may be curved, roundedor beveled.

[0025] It is understood, however, that the internal shape of the toolmay be so as to produce any desired or required outside shape of ahockey stick shaft. Further, while the above-described procedure hasbeen described as encasing the piece within two equally-sized tools, itis understood that the upper and lower cavity of the tool may not be ofthe same size, and one may be deeper than the other. In accordance witha further embodiment, the tool may be straight, or may impart a curve tothe shaft onto one or more surfaces of the shaft. Further, the curve tobe imparted may be in the direction of the longitudinal axis of theshaft, or may, for example, give a convex or concave curvature to one ofthe surfaces, in a transverse direction to the longitudinal axis of theshaft.

[0026] As discussed above, the piece is to be placed inside the tool forfurther processing and shaping. However, as the piece may be round whenthe mandrel is removed therefrom, and it is to be placed in anelongated, U-shaped cavity, the piece may need to be slightly deformed,i.e. pushed, so as to fit therein. This deformation may be made by hand.Once the piece is disposed inside the tool, i.e. inside the lowercavity, the upper cavity is placed over the piece so as to encase thepiece on all four sides. Once the piece is encased inside both upper andlower cavity, the bladder may be fitted with an attachment which mayallow for it to be filled with fluid, i.e. for example, air. The orderof the steps of affixing an attachment to the bladder and placing theupper cavity on the piece may be inverted. In addition, the bladder maybe fitted with the attachment before the piece is inserted into thetool.

[0027] Once the piece is enclosed in the tool and the attachment affixedto the bladder, the tool may be placed into a press. Alternatively, thetool may simply be clamped or held in such a manner that it does notopen up when pressure is applied to the bladder. One skilled in the artwill recognize that the tool may comprise more than one cavity, forexample up to four or more cavities so that the molding process may beaccomplished so as to produce more than one shaft at a time. Once thistool is disposed within the press, the bladders are inflated through theapplication of fluid pressure, i.e. air pressure.

[0028] The pressure which may be applied may be anywhere in the range of0 to 200 pounds per square inch. The pressure may be applied in avariety of manners, for example in a steady, even increase to a desiredlevel, and then maintained at that level for a specific period of time,i.e. for example the duration of the curing cycle. Alternatively, thepressure may be applied quickly, almost explosively, i.e. for a rapiddeformation of the piece, and maintained for a required period. In afurther alternative, the pressure may be applied in peaks or cycles, ormay be applied so that successively higher plateaus are achieved andmaintained for a period of time. The curing cycle may vary and may lastanywhere from 8 to 20 minutes or even longer, depending on thematerials, i.e. composite materials to be used, the combination thereofand the desired characteristics of the hockey stick shaft. In additionto the application of pressure, the press and/or the tool may be heatedor heat may otherwise be applied to the press and/or piece for theduration or for a part of the curing cycle. For example, the appliedtemperature may be increased up to and over 290° F., and maintained atthat temperature for all or part of the curing cycle. One skilled in theart will recognize that the combination of air pressure, appliedtemperature and length of curing cycle may vary in order to achieve therequired or desired result, or in accordance with the starting materialsused or in accordance to both.

[0029] It will be understood that the application of pressure to thebladder will cause said bladder to expand outwardly, i.e. to deformsomewhat, as the material to be used for the bladder may have someelasticity. The bladder, which through the application of air pressure,is made to expand outwardly (i.e. radially) pushes the prepregsoutwardly against the walls (i.e. inside the cavity) of the tool. As maybe understood, if sufficient pressure is applied to the bladder, thebladder may push the prepregs fully and completely outwardly against thewalls of the tool, such that the prepregs may take on the inside shapeof the tool, i.e. the outside dimensions of a finished hockey stickshaft will mirror the shape of the tool. The combination of sufficientair pressure, heat and time, may cause the prepregs to cure, i.e. tocause the resin impregnating the composite materials to cure, and tosolidify in the shape of the tool. As may be understood, the inside ofthe shaft may remain, hollow. Thus, the resulting hockey stick shaft mayhave a cross-sectional shape which is thin-walled, hollow and hasoutside dimensions which are similar if not identical to the insidedimensions of the tool, i.e. the U-shaped cavities cut into the lowermold and the upper mold. It will be understood that the pressure that isapplied, the length of time said pressure is applied and the temperaturewhich the tool is subjected to will be sufficient to ensure that thehockey stick shaft is fully formed and results in a solid shaft suitablefor its intended use.

[0030] Once the curing is complete, the tool is removed from the press,the top tool removed and the piece, now shaped like a hockey stick shaftis removed. Excess resin present may be removed from the-parting line,and the bladder may be removed from the inside of the shaft.Alternatively, the bladder may remain permanently inside the finishedshaft. The shaft may then be trimmed to size.

[0031] It is understood that the present invention discloses a method ofconstruction of a shaft, as well as the shaft itself constructed inaccordance with said method. Thus, in accordance with a particularembodiment of the present invention, there is provided with a:

[0032] A method of construction of a shaft made of composite materialscomprising the steps of: assembling a shaft portion from compositematerials, wherein said composite materials are not cured, said shaftportion having opposed first and second extremities, said shaft portioncomprising a hollow cavity disposed adjacent said first extremity, saidhollow cavity being in fluid communication with said first extremity;assembling a tenon made of composite materials, wherein said compositematerials are not cured, said tenon having a hollow first end sized andconfigured to be mated with said first extremity of said shaft portion;mating said hollow first end of said tenon with said first extremity ofsaid shaft portion to form a joint; applying internal pressure to saidjoint so as to bond said tenon to said shaft portion through theco-curing of said composite materials so as to form a unitary joint.

[0033] In accordance with a further embodiment, there is provided for a:

[0034] method of construction of a shaft comprising the steps of:selecting a mandrel sized to correspond to the desired shape of theshaft, disposing a bladder over the outside of said mandrel, applyingcomposite materials to the outside of said bladder, removing saidmandrel from the inside of said bladder, leaving behind said bladder andsaid composite materials applied therearound, disposing said bladder andsaid composite materials in a mold, applying air pressure to saidbladder such that said bladder expands, forcing said composite materialsto conform to the shape of said mold, keeping said air pressure appliedfor a sufficient time so as to allow the curing of said compositematerials to a rigid form.

DETAILED DESCRIPTION OF THE DRAWINGS

[0035] Other applications and advantages of the present invention may bemade clear by the following detailed description of several embodimentsof the invention. The description makes reference to the accompanyingdrawings in which:

[0036]FIG. 1 is an illustration of a composite hockey stick constructionpresently known in the prior art.

[0037]FIG. 2 is an illustration of an actual composite hockey stickconstruction presently known in the prior art.

[0038]FIG. 3 is a close-up of a tenon disposed inside a shaft showingthe excess adhesive of prior art composite stick construction.

[0039]FIG. 4 illustrates the stress riser of known composite hockeystick construction in the prior art.

[0040]FIG. 5 is a section of a scarf joint under construction.

[0041]FIG. 6 is a section of a scarf joint under construction showingthe mating of the tenon with the shaft.

[0042]FIG. 7 is a cross-section of a scarf joint being constructedshowing the application of internal bladder pressure.

[0043]FIG. 8 is a perspective view of a mandrel having a bladder beingfitted thereon.

[0044]FIG. 9 is a perspective view of a bladder fitted on a mandrel.

[0045]FIG. 10 is a perspective view of a strip of composite materialapplied on the outside of a bladder.

[0046]FIG. 11 is a perspective view of a mold with a piece about to befitted therein.

[0047]FIG. 12 is a front elevation view of the mold having a piecedisposed therein with an upper mold about to be disposed thereon.

[0048]FIG. 13 is a front and elevation view of the mold encasing thepiece showing the application of internal pressure and the deformationof the piece to fit inside the mold cavity.

[0049]FIG. 14 is a top plan elevation view of the bottom cavity of themold showing an alternative form of the cavity.

DESCRIPTION OF THE EMBODIMENTS

[0050]FIG. 1 is an illustration of a composite hockey stick constructionpresently known in the prior art. In particular, there is illustrated ablade 1 which is configured and disposed to be fitted into the hollowlower end 9 of a hockey stick shaft 3. The blade 1 comprises a palette 5from which projects a hosel portion 6 which hosel portion has a narrowerupper tenon 7. A shoulder portion 8 transitions the hosel 6 portion tothe tenon 7. The hockey shaft 3, having a lower hollow portion 9,comprises thin-walled members 11, and the hollow portion 9 is configuredand disposed to receive the tenon 7 therein. The thickness of thethin-walled portions 11 may be substantially the same as the size of theshoulder portion 8 such that once the tenon 7 is disposed inside thehollow portion 9, the outside surface 10 of hosel 6 may be flush withthe outside wall 12 of shaft 3. As indicated by motion arrows 13 and 15,the blade 1 is to be displaced such that tenon 7 snugly fits insidehollow portion 9. An adhesive 14 such as a glue or other type ofadhesive is disposed at the mouth end of hollow portion 9 such that thetenon 7 is firmly glued to the inside of the hollow portion once theblade 1 is moved therein. It is understood that the blade 1 and shaft 3may each be moved in the direction of motion arrows 13 and 15respectively, or that alternatively, only one of blade 1 or shaft 3 canbe moved. Further, it is understood that adhesive 14, rather than beingdisposed at the mouth of hollow portion 9, may instead be coated to thesurfaces of tenon 7 directly.

[0051]FIG. 2 illustrates an actual photo of the secondary bonding of ablade 1 to a shaft 3 as presently known in the prior art. As may beseen, the tenon is covered with adhesive and is shown as having beeninserted inside the hollow cavity of the shaft.

[0052]FIG. 3 is a close-up of the end of the tenon as inserted insidethe shaft and it shows the excess adhesive which may frequently be foundin this type of joint. Said excess adhesive of course adds nothing butweight and therefore decreases the serviceability of the stick.

[0053]FIG. 4 illustrates a graph showing the location of a stress riseralong the shaft constructed according to the teachings of the prior art,and shows where the weakness in a shaft may occur.

[0054]FIG. 5 illustrates an embodiment of the present invention, whereinthere is shown the construction of a composite shaft and blade whereinthere is no secondary bonding thereof. FIG. 5 therefore illustrates alower portion of a hockey stick shaft 25 under construction, comprisinga hosel 26 and a shaft 27. Hosel 26 is illustrated as coming to a point35 for further incorporation into a blade (not shown). Hosel 26 isillustrated as comprising a hollow core 28 and exterior thin walls 30surrounding hollow core 28. Further, hosel 26 is shown as having an openmouth 37 disposed at the top end thereof. Shaft 27 is illustrated ashaving a hollow portion 32 at its lower end, which hollow portion 32 isdefined by thin walls 39.

[0055] Thin walls 39 of shaft 27 and thin walls 30 of hosel 26 are madeof prepregs, which may be strips of composite materials which arepre-impregnated with resins such as epoxy resins, thermosetting resinsor any other resins. The composite materials themselves may be carbonfibres, Kevlar™, fibreglass, viscoelastic film adhesives and so on.Thus, thin walls 30 and 39 are constructed from a series of layers ofprepregs which have been previously applied (not shown). Subsequent tothe application of the prepregs, the curing thereof is not completed,such that the thin walls 30 and 39 are still malleable, while at thesame time retaining some structural shape. Thus, as may be understood,thin walls 30 and 39 are still soft, yet firm enough for handling anddisplacement.

[0056] Subsequent to the initial construction of hosel 26 and shaft 27,the open mouth 37 of hosel 26 and open mouth 41 of shaft 27 are disposedin close proximity 29 as illustrated in FIG. 5. A bladder 35 is disposedwithin hollow portion 28 and hollow portion 32 through any known means,such as, for example, through manual or mechanical application, orthrough the blowing of air therein such that it fills the cavities ofhollow portions 28 and 32. As illustrated, bladder 38 is closed at oneend and open for the introduction therein of fluids such as air at theother end (not shown). As illustrated, bladder 35 is shown as beingspaced apart from the walls of hollow portions 28 and 32 forillustrative purposes only but it is understood that either through itsintroduction therein, or through the blowing of air inside bladder 35,the walls of bladder 35 may abut and push against the walls of cavities28 and 32.

[0057]FIG. 6 illustrates the next step in the construction of theone-piece shaft construction. As shown, hosel 26 and shaft 27 are beingdisplaced towards each other in the direction of motion arrows 31 and33, causing a portion 43 of thin wall 30 of hosel 26 to collapseinwardly such that the thin wall 39 of shaft 27 can be disposed on theoutside thereof. Such a joint may be known as a scarf joint. Thecollapse of portion 43 of thin wall 30 of hosel 26 is made possible bythe fact that the prepregs used to construct thin wall 30 are not fullycured and therefore are soft and malleable to the extent necessary toallow sufficient deformation thereof.

[0058]FIG. 7 illustrates the next step in the construction of theone-piece shaft construction. As illustrated, hosel 26 and shaft 27 havebeen mated by the overlap of portion 43 of thin wall 30 of hosel 26 withthin wall 39 of shaft 27 which has produced an enlarged portion 47 atthe intersection 29 of the hosel 26 and shaft 27. As may be seen, due tothe increase of the thickness of the wall at section 29, walls 47portions are thicker than thin walls 30 and 39 immediately adjacentthereto. Once the mating is complete, air or other fluid can beintroduced inside bladder 35, causing bladder 35 to expand outwardly inthe direction of motion arrows 45. As illustrated, bladder 35 is shownas being spaced apart from the walls of the hosel and of the shaft forillustration purposes only. It is understood that once a sufficientamount of air is introduced inside bladder 35, same will expand to pushup and out against the inside walls of hosel 26 and shaft 35.

[0059] It is understood that the expansion of bladder 35 need be done insuch a manner that the outside walls 47 and 49 of hosel 26 and shaft 27respectively are made to push out against a form, mold or die. It willbe understood that the absence of this form will simply mean that thebladder will expand until it bursts. Although not shown, the hosel26/shaft 27 combination as illustrated in FIG. 7 may be, prior to theexpansion of bladder 35 (complete expansion) to be placed in a mold,cavity or other form which will enable the inner pressure applied bybladder 35 to create the final form of the hosel 26 and shaft 27. Inparticular, overlap of portion 29 is subjected to the outward pressure45 of bladder 35 so as to create the co-curing of the prepregs of thethin wall 30 of hosel 26 with the prepregs of thin wall 39 of shaft 27.Heat may also be applied to cure, or assist in the curing of theprepregs.

[0060]FIG. 8 illustrates a further embodiment of the present invention,wherein a mandrel 50 is illustrated immediately prior to the fittingthereon of a bladder 52 in the direction of motion arrows 54. As may beseen, mandrel 50 is generally cylindrical in shape, having an elongatedform which may be sized so as to be longer (i.e. slightly longer) thanthe desired length of the finished shaft. Mandrel 50 is shown as beingsolid but it is understood that it can, if required or desired, bethin-walled and/or hollow. Bladder 52 is illustrated as beingconstructed of a thin-walled material, such as nylon, rubber, silicon orlatex, sized and configured to fit over mandrel 50 from one end thereofto the other.

[0061]FIG. 9 illustrates a mandrel 50 having the bladder 52 disposedthereon. As may be seen, bladder 52 comprises a closed end 56 and anopen end 58. Open end 58 may be fitted with an adapter (not shown) forthe introduction of air therein.

[0062]FIG. 10 illustrates a further step in the construction of acomposite shaft. As may be seen, mandrel 50 has been fitted thereon witha bladder 52. A strip of prepreg 60 is shown as having been applied onthe outside of bladder 52, from one end of the mandrel 50 to the otherend thereof. As illustrated, prepreg 60 is shown as being a relativelythin elongated strip of composite material which has been wound about atan angle vis-à-vis the longitudinal axis of mandrel 50. For illustrationpurposes, it will be understood that a number of further strips ofprepregs 60 will be necessary to fully cover the outside of the bladder.It will be further understood that further prepregs 60 may be applied ina similar manner to that shown in FIG. 10, i.e. at the same angle inrelation to the longitudinal axis, or alternatively, at a differentangle. For example, one or more additional layer of prepregs might beadded so that the orientation of the prepregs may be disposed at 90° tothe orientation of the prepreg 60 illustrated in FIG. 10. In addition,prepreg strips may be applied longitudinally, i.e. from one extremity ofmandrel 50 to the other without any twisting thereabout. Further,prepregs can be applied in small strips which simply circle once aboutthe mandrel 50. It is further understood that prepregs can be applied inany number of combinations or variations as described above and that anumber of layers of prepregs can be applied, each layer being similarand/or different in its application than that illustrated in FIG. 10.

[0063] The prepregs 60 may be applied either manually or mechanically ora combination of both. As they are applied, a small amount of pressureis applied thereon such that the prepregs adhere to the underlyingsurface, however this pressure may not be sufficient to cure, i.e.completely cure the prepregs to their final form.

[0064] Once the prepregs 60 have been applied to the outside of thebladder 52, mandrel 50 is removed in the direction of motion arrow 62.As may be understood, mandrel 50 may be tightly disposed within bladder52 and may require some twisting and/or pulling to dislodge same fromwithin bladder 52.

[0065]FIG. 11 is a perspective view of the piece 64 about to be insertedinto a tool 69. Tool 69 is illustrated as comprising a body 70 which maybe made of any suitable material, for tool or dies, such as steel,brass, aluminum or ceramic. The tool comprises a cavity 71 which isshown for illustration purposes only as being short. It is understood,however, that said cavity 71 is to be used to shape the shaft of ahockey stick, and can therefore be up to 60 or 72 inches long. Cavity 71comprises four surfaces, namely bottom surface 72, opposed-side surfaces74 and rear surface 76. It is understood that the configuration anddisposition of cavity 71 is to be similar to the outside final shape ofthe desired hockey stick shaft. Thus, if it is required or desired thatthe outside surfaces of the finished hockey stick be flat (i.e. withouta curve), bottom surface 72, opposed-side surfaces 74 and rear surface76 will be of a correspondingly flat shape (i.e. without any orsubstantially any curve). It is also understood that opposed-sidesurfaces 74 may be parallel to each other, but if the final shape of thehockey stick shaft is to be other than having parallel-side surfaces,opposed-side surfaces 74 may not be parallel to each other but mayinstead converge to a point, either throughout the length of the cavity71 or alternatively, the convergence may begin at or near one extremityof cavity 71. Further, cavity 71 may comprise round and/or beveledcorners where, for example, bottom surface 72 intersects side surface74. In addition, surfaces 72, 74 and 76 may be concave or convex.

[0066] Piece 60 comprises, as described above, a bladder 52 onto whichhave been rolled or applied prepregs 60 such that the outside surface ofbladder 52 is completely covered therewith.

[0067] The dimension (i.e. cross-sectional dimension of cavity 71) isrelated to the cross-sectional dimension of piece 64. As may beunderstood, piece 64 is to fit inside cavity 71, and once theapplication of air pressure to the inside of the bladder is effected,the deformation of piece 64 will occur such that all (substantially allof the volume of cavity 71) is to be filled with the(a?) piece. Thus,since the prepregs have a limited linear elasticity, but can however bedeformed to fit a shape, the circumference of the piece 64 is to besimilar, i.e. slightly smaller than the circumference of thecross-sectional area of cavity 71 as illustrated in FIG. 12. As may beunderstood, a slight amount of deformation will be required in order tofit piece 64 inside cavity 71, however said deformation may beaccomplished due to the fact that the prepregs are not fully cured andare therefore still malleable while retaining some stiffness.

[0068]FIG. 12 illustrates a front end elevation view of the tool 69 ofFIG. 11. As may be seen, piece 64 has been inserted inside cavity 71 oftool 69. As illustrated, parts of the outside surface of prepregs 60 maybe in contact with bottom surface 72, opposed-side surfaces 74 and rearsurface 76 (not shown). As may be seen, cavity 71 is configured anddisposed so that approximately half of piece 64 fits therein. Further,top piece 80, a substantial mirror image of piece 69, is shown as beingdisplaced downwardly so as to meet tool 69 and so as to encase piece 64therein. Although top tool 80 and tool 69 are shown as beingsubstantially similar, it is understood that cavity 71 may, for example,be configured and disposed such that it fits more or less than half ofpiece 64 therein. In a further embodiment, it is understood that cavity71 may, for example, be able to fit the whole of piece 64 therein, andupper tool 80 would in this case simply be a flat lid which serves toprovide a top surface without any side surfaces.

[0069]FIG. 13 illustrates the next step in the construction of theone-piece shaft, wherein the upper tool 80 has closed down on top oftool 69, fully encasing piece 64 within cavities 71 and 79. Asillustrated, piece 64 is shown as being in the process of being inflatedoutwardly by the air pressure being applied inside bladder 52 such thatit is deforming in the direction of motion arrows 82. Although shown notfully occupying the whole of the volume of cavities 71 and 79, throughthe sufficient application of air pressure, piece 64 will eventuallydeform fully so that it takes the shape of opposed-side surfaces 74 and75, as well as bottom surface 72 and top surface 73.

[0070]FIG. 14 illustrates a top plan view of an alternative tool 80similar to that shown in FIG. 11. Cavity 84 is shown as havingsubstantially the shape of a hockey stick shaft, wherein the surfaces ofbottom-most portion 86 are shown as being angled towards each other.

I claim:
 1. A method of construction of a shaft made of compositematerials comprising the steps of: a. assembling a shaft portion fromcomposite materials, wherein said composite materials are not cured,said shaft portion having opposed first and second extremities, saidshaft portion comprising a hollow cavity disposed adjacent said firstextremity, said hollow cavity being in fluid communication with saidfirst extremity; b. assembling a tenon made of composite materials,wherein said composite materials are not cured, said tenon having ahollow first end sized and configured to be mated with said firstextremity of said shaft portion; c. mating said hollow first end of saidtenon with said first extremity of said shaft portion to form a joint;d. applying internal pressure to said joint so as to bond said tenon tosaid shaft portion through the co-curing of said composite materials soas to form a unitary joint.
 2. The method of construction of claim 1wherein the application of pressure is effected through the introductionof a bladder inside said hollow cavity and said hollow first end priorto the mating thereof, said bladder being inflated such that itpressures the curing together of the composite material of said tenonand of said shaft portion.
 3. The method of construction of claim 2wherein prior to the application of said internal pressure to saidbladder, said mated shaft portion and tenon are disposed inside a mold.4. The method of construction of claim 1 wherein the composite materialsof said shaft portion and of said tenon are not subjected to pressureprior to said mating.
 5. The method of construction of claim 1 whereinsaid composite materials of said shaft portion and of said tenon areuncured prior to said mating.
 6. The method of construction of claim 1wherein said composite materials of said shaft portion and of said tenonare subjected to some pressure prior to mating.
 7. The method ofconstruction of claim 1 wherein the mating occurs through the insertionof said hollow first end of said tenon inside said first extremity ofsaid shaft portion.
 8. The method of construction of claim 1 wherein themating occurs through the insertion of said first extremity of saidshaft portion inside said first end of said tenon.
 9. The method ofconstruction of claim 2 wherein said bladder is internally disposedsubstantially along the whole length of said shaft and of said tenon.10. The method of construction of claim 1 wherein said shaft is a shaftsuitable for use with sporting equipment.
 11. The method of constructionof claim 10 wherein said shaft is a hockey stick shaft.
 12. A method ofconstruction of a shaft comprising the steps of: a. selecting a mandrelsized to correspond to the desired shape of the shaft; b. disposing abladder over the outside of said mandrel; c. applying compositematerials to the outside of said bladder; d. removing said mandrel fromthe inside of said bladder, leaving behind said bladder and saidcomposite materials applied therearound; e. disposing said bladder andsaid composite materials in a mold; f. applying air pressure to saidbladder such that said bladder expands, forcing said composite materialsto conform to the shape of said mold; g. keeping said air pressureapplied for a sufficient time so as to allow the curing of saidcomposite materials to a rigid form.
 13. The method of construction ofclaim 12 wherein said mold comprises a lower mold portion and an uppermold portion, wherein said bladder and said composite materials aredisposed in said lower mold portion prior to the application of said airpressure, said upper mold portion being disposed over said lower moldportion so as to encase said bladder in said composite materials priorto the application of said air pressure to said bladder.
 14. The methodof construction of claim 12 wherein said mold is configured and sized soas to impart to said composite materials the shape of a hockey stickshaft.
 15. A method of construction of claim 12 wherein the air pressureapplied is in the range of 0 to 200 P.S.I.
 16. The method ofconstruction of claim 15 wherein the air pressure is applied in asmooth, continuous gradient up to its required pressure.
 17. The methodof construction of claim 15 wherein the air pressure is applied in aninitial rapid burst up to the desired pressure and then maintained forthe duration of the curing.
 18. The method of construction of claim 15wherein heat is applied to the mold during the curing of said compositematerials.
 19. The method of construction of claim 15 wherein the moldis heated prior to the introduction of said bladder and said compositematerials and wherein the heat of the mold is increased during saidcuring.
 20. The method of construction of claim 15 wherein said bladderis made from a group of materials comprising nylon, silicone, rubber andlatex.
 21. The method of construction of claim 15 wherein said compositematerials are selected from a group comprising carbon fibers,fiberglass, Kevlar™ and viscoelastic films.
 22. The method ofconstruction of claim 15 wherein the mold comprises a mold cavity whichcavity comprises opposed, spaced apart, top and bottom surfaces, andopposed left and right surfaces spacing apart said top and bottomsurfaces.
 23. The method of construction of claim 22 wherein said topand bottom surfaces are flat.
 24. The method of construction of claim 22wherein said top and bottom surfaces are parallel to each other.
 25. Themethod of construction of claim 22 wherein one or more of said topsurface, bottom surface, left surface and right surface is curved. 26.The method of construction of claim 15 wherein said left and rightsurfaces are parallel to each other for a portion of the mold cavity andconverge to a narrower point adjacent to one extremity thereof.
 27. Ashaft constructed using the method of construction of claim
 15. 28. Theshaft of claim 27 wherein said shaft is a hockey stick shaft.